SY58021U
4GHz, 1:4 LVPECL Fanout
Buffer/Translator with Internal Termination
Precision Edge®
General Description
The SY58021U is a 2.5V/3.3V precision, high-speed, fully
differential 1:4 LVPECL fanout buffer. Optimized to provide
four identical output copies with less than 15ps output
skew and only 70 fsRMS phase jitter, the SY58021U can
process clock signals as fast as 4GHz.
The differential input includes Micrel’s unique, 3-pin input
termination architecture interfaces to differential LVPECL,
CML, and LVDS signals (AC- or DC-coupled) as small as
100mV without any level-shifting or termination resistor
networks in the signal path. For AC-coupled input interface
applications, an on-board output reference voltage (VREFAC)
is provided to bias the VT pin. The outputs are 100k
LVPECL compatible, with extremely fast rise/fall times
guaranteed to 70fs.
The SY58021U operates from a 2.5V ±5% supply or 3.3V
±10% supply and is guaranteed over the full industrial
temperature range (–40°C to +85°C). For applications that
require faster rise/fall times, or greater bandwidth, consider
the SY58022U 1:4 fanout buffer with 400mV LVPECL
output swing, or the SY58020U 1:4 CML fanout buffer. The
®
SY58021U is part of Micrel’s high-speed, Precision Edge
product line.
Data sheets and support documentation can be found on
Micrel’s web site at www.micrel.com.
Precision Edge®
Features
• Precision 1:4 LVPECL fanout buffer
• Low jitter performance:
− 70fsRMS phase jitter (typical)
• Accepts an input signal as low as 100mV
• Unique input termination and VT pin accepts DCcoupled and AC-coupled differential inputs: LVPECL,
LVDS, and CML
• 100k LVPECL-compatible 800mV swing output
• Power supply 2.5V ±5% and 3.3V ±10%
• −40°C to +85°C temperature range
• Available in 16-pin (3mm × 3mm) QFN package
Applications
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All SONET and GigE clock distribution
Fibre Channel clock and data distribution
Backplane distribution
High-end, low-skew, multiprocessor, synchronous clock
distribution
Block Diagram
Precision Edge is a registered trademark of Micrel, Inc.
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
September 2011
M9999-090111-B
hbwhelp@micrel.com or (408) 955-1690
